1. Field of the Invention
This invention relates to a method of removing calcium oxide containing residual slag incrustations from surfaces in the presence of which molten iron has been desulfurized by contacting the incrustations with a source of an oxide of boron such as B.sub.2 O.sub.3 or a boron oxide mineral. More particularly, the present invention is directed to an inexpensive and effective method of removing calcium oxide containing residual slag incrustations from vessels including torpedo ladles employed in the desulfurization of pig iron. The present invention is particularly directed to increasing the capacity of torpedo ladles which have been employed in the desulfurization of pig iron and as a result of such desulfurization have built up a considerable layer of calcium oxide containing residual slag incrustation.
2. Discussion of the Prior Art
In the desulfurization of molten raw iron, especially when torpedo ladles are used for transporting the raw iron from the blast furnace first to a desulfurization system and then, after treatment is completed, to the steelworks, incrustations and deposits of solid residual slag form on the bottom and walls of the ladle after several round trips, if desulfurizers containing calcium are used. In severe cases this results in an appreciable accumulation of residual slag in the torpedo ladle, diminishing the raw iron transporting capacity of the torpedo ladle.
To break up these deposits and "flush out" the torpedo ladle, it has hitherto been the practice after several round trips to treat the molten raw iron exclusively with soda. Such a procedure, however, has the disadvantage that the desulfurization treatment with the calcium-containing desulfurizer has to be interrupted, resulting in operational difficulties in supplying the raw iron with the required quality. Furthermore, very large amounts of soda have to be used in flushing out the torpedo ladle.
The object of the invention consists in avoiding the disadvantages of the previous method of procedure and providing a method whereby it will become possible to remove the residual slag incrustations from the vessel, especially from the torpedo ladle, without interrupting the chosen desulfurization procedure using desulfurizers containing calcium.